A facile hydrothermal approach to the synthesis of nanoscale rare earth hydroxides.

Li C, Liu H, Yang J - Nanoscale Res Lett (2015)

Bottom Line:
Nanosized rare earth (RE) hydroxides including La(OH)3, Nd(OH)3, Pr(OH)3, Sm(OH)3, Gd(OH)3, and Er(OH)3 with rod-like morphology are fabricated via a convenient hydrothermal approach.CeO2 nanoparticles with spherical shape could be directly obtained by hydrothermal treatment of complexes formed between Ce precursors and DDA.In addition, by further calcinating the RE hydroxides at high temperature in air, RE oxide nanorods could be readily produced.

ABSTRACTNanosized rare earth (RE) hydroxides including La(OH)3, Nd(OH)3, Pr(OH)3, Sm(OH)3, Gd(OH)3, and Er(OH)3 with rod-like morphology are fabricated via a convenient hydrothermal approach. This strategy calls for the first preparation of metal complexes between RE precursors and dodecylamine (DDA) in water/ethanol mixture at room temperature and subsequent thermal decomposition at elevated temperature. The influence of reaction time and water/ethanol volume ratios on the morphology and size of as-prepared RE hydroxides are investigated. CeO2 nanoparticles with spherical shape could be directly obtained by hydrothermal treatment of complexes formed between Ce precursors and DDA. In addition, by further calcinating the RE hydroxides at high temperature in air, RE oxide nanorods could be readily produced.

Fig3: TEM images of La(OH)3nanorods. Prepared under different reaction times and water/ethanol volume ratios: (a-d) 6, 12, 18, and 24 h while DDA volume and water/ethanol volume ratio are fixed at 5 mL and 1/1, respectively; (e-h) water/ethanol volume ratio of 100/0, 80/20, 20/80, and 0/100 while DDA and reaction time are fixed at 5 mL and 18 h, respectively.

Mentions:
Taking La(OH)3 as a typical example, we have conducted a series of experiments under different hydrothermal conditions to investigate the growth of RE hydroxide nanorods. We found that the reaction time and water/ethanol volume ratio have significant influence on the size and morphology of the RE hydroxides, while the effect from the hydrothermal temperature and DDA/RE precursor ratio is only slight. Figure 3a,b,c,d shows the TEM images of La(OH)3 nanorods as prepared by hydrothermal treatment of La(NO3)3-DDA complexes at 180°C for 6, 12, 18, and 24 h, respectively. At 6 h, only short La(OH)3 nanorods are observed under TEM (Figure 3a). At longer time (12 h), the length of the nanorods become larger while the diameter of the rods are remained (Figure 3b), indicating that the anisotropic growth of La(OH)3 occurs along the axial direction. After 18 h, the La(OH)3 nanorods are fully developed, and further increase in reaction time would not alter the morphology and size of the final La(OH)3 nanorods (Figure 3c,d).Figure 3

Fig3: TEM images of La(OH)3nanorods. Prepared under different reaction times and water/ethanol volume ratios: (a-d) 6, 12, 18, and 24 h while DDA volume and water/ethanol volume ratio are fixed at 5 mL and 1/1, respectively; (e-h) water/ethanol volume ratio of 100/0, 80/20, 20/80, and 0/100 while DDA and reaction time are fixed at 5 mL and 18 h, respectively.

Mentions:
Taking La(OH)3 as a typical example, we have conducted a series of experiments under different hydrothermal conditions to investigate the growth of RE hydroxide nanorods. We found that the reaction time and water/ethanol volume ratio have significant influence on the size and morphology of the RE hydroxides, while the effect from the hydrothermal temperature and DDA/RE precursor ratio is only slight. Figure 3a,b,c,d shows the TEM images of La(OH)3 nanorods as prepared by hydrothermal treatment of La(NO3)3-DDA complexes at 180°C for 6, 12, 18, and 24 h, respectively. At 6 h, only short La(OH)3 nanorods are observed under TEM (Figure 3a). At longer time (12 h), the length of the nanorods become larger while the diameter of the rods are remained (Figure 3b), indicating that the anisotropic growth of La(OH)3 occurs along the axial direction. After 18 h, the La(OH)3 nanorods are fully developed, and further increase in reaction time would not alter the morphology and size of the final La(OH)3 nanorods (Figure 3c,d).Figure 3

Bottom Line:
Nanosized rare earth (RE) hydroxides including La(OH)3, Nd(OH)3, Pr(OH)3, Sm(OH)3, Gd(OH)3, and Er(OH)3 with rod-like morphology are fabricated via a convenient hydrothermal approach.CeO2 nanoparticles with spherical shape could be directly obtained by hydrothermal treatment of complexes formed between Ce precursors and DDA.In addition, by further calcinating the RE hydroxides at high temperature in air, RE oxide nanorods could be readily produced.

ABSTRACTNanosized rare earth (RE) hydroxides including La(OH)3, Nd(OH)3, Pr(OH)3, Sm(OH)3, Gd(OH)3, and Er(OH)3 with rod-like morphology are fabricated via a convenient hydrothermal approach. This strategy calls for the first preparation of metal complexes between RE precursors and dodecylamine (DDA) in water/ethanol mixture at room temperature and subsequent thermal decomposition at elevated temperature. The influence of reaction time and water/ethanol volume ratios on the morphology and size of as-prepared RE hydroxides are investigated. CeO2 nanoparticles with spherical shape could be directly obtained by hydrothermal treatment of complexes formed between Ce precursors and DDA. In addition, by further calcinating the RE hydroxides at high temperature in air, RE oxide nanorods could be readily produced.